Old Lennox draft G12D2 82,000 in / 62,000 out, used in an apartment with a worst case heat loss around 20,000. Five minutes of heat, hour of shivers, five minutes of heat....
Given that no landlord will replace anything until a red tag goes on (and this HX isn't dead yet, pity) ... has anyone ever gone to smaller orifices in a case like this? how much of a difference is achievable in practice? any problems likely as long as delta T is kept above 70F (spec is 70 - 100)?